Everything he said is true but many competitors aren't striving for a Top-50 finish. This event is totally achievable for most runners/walkers as long as you train for long days on your feet and prepare accordingly. This means running/walking within your ability for 5-10hrs at a time over multiple days and reading/researching and testing your nutrition, hydration and kit to ensure you are in control from day 1.
The so-called 'toughest footrace on earth' is VERY tough. But it's also an amazing experience that will test you mentally as much as physically. We are all capable of more than we think so be prepared to challenge your own limiting beliefs.
*Worth noting that Tobias Mews is a running machine and I'm not convinced he's even human.